Satellite links are characterized by rather high RLC (Radio Link Control) RTT (Round Trip Time), typically longer than 500-1000 ms, which are difficult to handle using conventional fixed RLC timer values. Such timer values are usually applied in more conventional links with a significantly lower RLC RTT, i.e. typically shorter than 100-200 ms. Therefore, the satellite links require special tables or entries in existing tables with suitable RLC timer values.
A drawback of such approach is that the radio network controller of the radio communication network has to include rules that select which RLC timer values should be used for each link. Further, the tables may be extensive, in particular if the radio communication system supports multiple radio bearer combinations, since unique RLC timer values have to be stored for each radio bearer. In addition, each new radio bearer that is added, needs to be assigned unique RLC timer values leading to additional table updates and maintenance work.
A further drawback is that different satellite links may have different latency characteristics and therefore a fixed set of RLC timer values for all satellite links may not be optimum, or functional problems may occur. A table based solution with fixed timer values has typically to take worst case scenarios into consideration, which leads to too conservative timer values. As a result, the throughput and the latency are adversely affected.
Particularly, in radio communication systems having high BLER (Block error Rate), high RLC RTT deteriorates system performance, and optimum RLC timer values are thus especially important in such systems.